Preparation And Electrocatalysis Research Of Electrocatalysts Of Direct Oxidated Fuel Cells

Direct oxidated fuel cells, the fuels of which are small organic molecules such as methanol, ethanol, propanol and formic acid are the new types of low temperature fuel cells. The poisoning of the anode electrocatalysts has affected entire power, current density, performance and service life of fuel cells. In order to solve this problem, researchers are all devoted in the research of modification of metal or oxide to Pt.In this paper, we prepared oxides modifying Pt and PtRu electrocatalysts using sol-gel and alcohol-reduction methods, researching the influence of pH value of the system, calcining temperature of the oxide powders, temperature treating and the ratio of molecules to the electrocatalysts preparation. Particle sizes, distributions and element contents of the composited catalysts were characterized using XRD, EDS and FETEM. The catalyst average grain diameters and interaction with various components have the crucial influence to its catalytic activity. This is because the joining of metal can display the bi-function and synergism, increasing the ability of Pt surface adsorption oxygen-containing compounds and reducing its oxidized potential through changing electron distribution of d orbitals of Pt; on the other hand, adding oxides can provide oxygen-containing group, reduce the poisoning and speed up the occurrence of oxidizing action through releasing the active position of Pt surface.In methanol electrooxidation, adding TiO2 or the Ru promoter to Pt can promote the methanol catalyst electrochemistry oxidizing reaction on Pt. While simultaneously dopes Ru and TiO2 have better effect. But rare-earth metal compound oxide compound CexPr1-xOy modifying PtRu performance exceed modifying TiO2 to PtRu electrocatalyst; in ethanol electrooxidation, Pt-SnO2/C exhibits the best electrocatalysis in the conidition of pH=10, calcining temperature of 650℃and Pt:Sn = 2:1. This catalyst possesses the high stablities and electro-activities during the electrooxidation of ethanol, taking on a better electrocatalysis than Pt/C. In this foundation, inspect the performance of PtRu-TiO2/C and Pt-SnO2/C in the solution of formic acid and ethylene glycol. The performance of catalyst PtRu-TiO2/C is inferior to PtRu/C,while catalyst Pt-SnO2/C is superior to Pt/C in the above two kind of solution. This paper has also carried on the exploration and the discussion to the above organic small molecular reaction mechanism as well as the influence factor.